Fair Value Measurements Cash, Cash Equivalents and Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Sep. 30, 2014	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
CashCashEquivalentsAndShortTermInvestmentsAmortizedCost	$ 13,081	$ 28,999
CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses	5
Cash, Cash Equivalents, and Short-term Investments	13,076	28,999
Cash Equivalents, at Carrying Value	2,999	28,999
Available-for-sale Securities, Current	10,077
Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
CashCashEquivalentsAndShortTermInvestmentsAmortizedCost		9,006
Cash, Cash Equivalents, and Short-term Investments		9,006
Cash Equivalents, at Carrying Value	0	9,006
Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
CashCashEquivalentsAndShortTermInvestmentsAmortizedCost	2,999	19,993
Cash, Cash Equivalents, and Short-term Investments	2,999	19,993
Cash Equivalents, at Carrying Value	2,999	19,993
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
CashCashEquivalentsAndShortTermInvestmentsAmortizedCost	5,076
CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses	5
Cash, Cash Equivalents, and Short-term Investments	5,071
Available-for-sale Securities, Current	5,071
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Current	5,006
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
CashCashEquivalentsAndShortTermInvestmentsAmortizedCost	5,006
Cash, Cash Equivalents, and Short-term Investments	$ 5,006